


Superhero-sized Heart

by manamune (orphan_account)



Category: Haikyuu!!
Genre: M/M, iwaizumi is batman, iwaoi adopt a kid for roughly two hours
Language: English
Status: Completed
Published: 2015-07-20
Updated: 2015-07-20
Packaged: 2018-04-10 05:48:33
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,508
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/4379618
Author URL: https://archiveofourown.org/users/orphan_account/pseuds/manamune
Summary: <blockquote class="userstuff">
              <p>Iwaizumi loathes the day he has to tell the story of how he met Oikawa, because then he's going to have to explain why he suddenly grabbed him by his collar with a crying four-year old boy trailing behind him while dressed as Batman on the hottest day of the year.</p>
            </blockquote>





	Superhero-sized Heart

**Author's Note:**

> for drey

Iwaizumi doesn’t even know why he comes to these things.

That’s a lie. He knows exactly why. He’s _usually_ personable, he likes people and more importantly, likes talking to people, especially about shared interests. What he _doesn’t_ know is why he chooses to put himself through the discomfort of dressing up and standing awkwardly outside the door, unable to afford a pass since he spent it all on his Batman costume.

 _I look ridiculous,_ he grumbles, absently picking at his gloves to try and imitate the actions of a person who isn’t alone, bored, and embarrassed. He’s dressed as Batman and it’s way too hot for this. The sun beats down on the leather costume and he groans, leaning against the wall _. I’m not dressing up next time. Going normally and spending the money on a pass would be way better than this…_

He debates just going home, but he drove all the way here from out of the city and it’d feel even sillier to come back just a few hours later. His roommate would certainly enjoy it, the sadistic bastard.

He moves his bags to the shade at the entrance of the convention building and slides down onto a bench, watching as people walked in and out of the convention hall. Lots of other people were chatting in the area, probably not having passes themselves, but that was different. At least they had people to talk to. He sighs and closes his eyes, glad that, at the very least, he managed to grab a spot out of the sun.

It feels like forever until he hears a small, shy voice. Iwaizumi opens one eye and sees a kid, barely reaching up to the height of the bench, clutching a Batman doll in his tiny arms. “Um…”

His mom, a petite lady with pretty red hair, a soft smile, and a pale pink shirt, is behind him, lightly nudging him foward. “Go on, it’s alright.”

The boy looks up at him with big, wet eyes, and Iwaizumi instantly recognizes that childish adoration. He’s met a lot of kids—way more than adults—and he smiles even though he’s tired, leaning his arms onto his knees.

“Hey,” Iwaizumi says, and the kid makes a noise like a squeak and holds his Batman doll tighter. His mom laughs and takes a step back and the kid wobbles with uncertainty, looking back between the floor and Iwaizumi.

“Batman,” the boy starts, slowly holding out his Batman doll and a sharpie he fished out from his pockets—Iwaizumi was almost afraid that it would drop out with how small they were. “W-Will you sign this for me?”

Iwaizumi takes the doll like it’s a treasure, because to the boy, it probably is. Those huge eyes look at him with the weight of a whole childhood of expectations, and Iwaizumi gulps. It’s way more difficult to talk to kids, who think he’s real and that he fights crime when he’s not sitting around in the burning sun outside of an anime and comic convention.

“This is a good one of me.” Iwaizumi holds the doll in his palm and the kid nods quickly, wringing his hands tighter. “Are you sure you want me to put permanent marker on it?”

“You’re my favourite,” the boy says, then smiles. Iwaizumi smiles back, although he’s sure it’s not very evident beneath the mask. He uncaps the marker and then rests the doll safely onto his lap, writing his name onto the leg of the doll. Not his real name, of course, but ‘BATMAN’ in big, blocky English letters. He takes time to make sure that the marker doesn’t smudge, and then he blows on it for good measure before handing it back to the kid. He’ll give the marker to his mom, though; he’s not sure if he trusts this quivering boy with something potentially toxic.

The boy immediately takes the doll from his hands, grasping it in happiness. He looks in amazement at the signature on the doll’s thigh and his smile only gets wider. He’s a cute kid, with soft dark brown hair and a pearly smile when it’s big and bright.

But the smile is off his face within moments when the boy turns around and calls to the air, “Mom?”

_Oh, no._

Iwaizumi looks around, but there’s no sign of the kid’s mom in sight. Usually, it would be easy. Red hair isn’t exactly common, but in the sea of cosplayers and generally eccentric people that have gathered for the convention, it became a million times harder. He stands up to try and get a better view, but even while looking above the heads of most of the people in the crowd, he can’t spot her.

“Mom?” the boy wails this time. Iwaizumi hears the beginning of a sob, and then he turns to Iwaizumi and clutches the leather of his pants. “M-Mom,” he hiccups. Iwaizumi isn’t sure if he’s asking Iwaizumi to help find his mom, or if Iwaizumi is now his substitute parent.

He quickly shoves the market into his bag. “Kid,” Iwaizumi tries to keep his voice low and gentle, but not intimidating. He’s not entirely sure how the real Batman would react to this, since there’s a million different versions of him and he’s certainly more gloomy than Iwaizumi, but he doesn’t want to break character and ruin this boy’s dreams. “Don’t worry, she’s around here somewhere. I’ll help you find her.”

“Moooom,” the boy sobs, apparently not listening to a single word Iwaizumi says. Iwaizumi reaches for his little hand, shifting the doll to his other arm. He grabs his bag with his free hand and slings it around his shoulder before surveying the crowd again.

He doubted she would go inside without her child, so she must be somewhere outside still. His immediate area isn’t very big, but there’s a parking lot and a public park nearby where people have been congregating all afternoon.

“Stay close,” Iwaizumi says, and slowly begins to walk. The boy nods against his leg and follows, only walking when Iwaizumi does. He hiccups every so often, a small whine or ‘Mom’ that slowly begins to gnaw away at Iwaizumi’s heart every time he does it.

He guides the kid through the crowd, always on the lookout for a familiar head of red hair even if the boy isn’t, too busy whimpering to Iwaizumi and playing with the ends of his cape. Iwaizumi lets him; he’s far too small and distressed to actually do any damage to the precious fabric.

“Ah,” Iwaizumi breathes a sigh of relief when he sees a head of dark red walk past. “Hey! Wait—!” He catches the sleeve of the kid’s mom and she turns around, eyebrows furrowed, lips frowning, and _Oh_ , Iwaizumi realizes a little too late that this person was definitely not this boy’s mom.

“Um,” the person that Iwaizumi managed to catch looks from Iwaizumi, to the kid at his feet, and back to Iwaizumi. They’re pretty, _really_ pretty, but most certainly not this kid’s mom, and a rush of embarrassment falls to the pit of Iwaizumi’s stomach. There’s a volunteer sticker taped to the front of their shirt, but Iwaizumi is too embarrassed to stare at them too long to actually read out the name. “Can I help you?”

He tries to play it off smooth, but it’s difficult when the boy sees the person who looks like his mom but is _not_ his mom and sobs even louder. “I-I’m trying to find this boy’s mom. Is there a, uh, lost and found or something?”

The person laughs, “A lost and found for children?”

The boy squeaks out, ‘Mom,’ and slowly moves from clutching Iwaizumi to the volunteer’s leg. They’re wearing pretty pastel shorts and a white tank top—clearly dressed for the weather, unlike Iwaizumi, and he belatedly notices that he inversed the colours of their clothes by accident. The volunteer smiles at the kid and pats his head twice.

Iwaizumi shifts awkwardly on his feet, feeling rather alone again. “I just want to find his mom.”

“Most people don’t bring their kids here so we don’t have an official help desk for that, but I can try and help.” They pull out a clipboard from their bag. There’s a pen attached to the top and they begin to scribble something down, the kid absently playing with the arms of the Batman doll. Every moment that passes with the kid sniffling and the sun beating against him makes him feel steadily worse and worse. “Can I know your name?”

He lowers his voice so the kid doesn’t hear. “Iwaizumi Hajime. I’m not… this child’s father.”

The person grins at him and Iwaizumi realizes that was the wrong thing to say, by the way their eyes twinkle with amusement. “Trust me, I know.” They look down at the kid after, patting his head again. “And what’s your name?”

“Hayama,” is all he says.

“Is that your first or last name?” They continue to pet the kid’s hair, and it seems to help, by the way he shakes less like a leaf and more like a scared little boy. Which in Iwaizumi’s eyes, is an improvement.

“It’s… Hayama… Yu… Ya… Ta? Um…”

The volunteer shushes him quietly. “It’s alright, Hayama-kun. Don’t worry about it, I was just wondering. We can still find your mom.”

Hayama nods quickly and looks at the volunteer with sparkling eyes. Iwaizumi’s pretty sure that he’s found his new favourite superhero.

“I’m Oikawa Tooru,” they say and then point to the badge on their chest. “I’m twenty-three, I’m a boy, I like sci-fi movies, and I go to an art university.”

Iwaizumi blinks at the information overload. “Uh,” he pauses, not sure what to say. “What?”

Oikawa laughs loudly and pockets the clipboard back into his bag. It has blue and pink polka-dots on it and it looks rather childish—but if he’s an art student, then Iwaizumi isn’t nearly as surprised. “I’m supposed to tell you about myself to make you more comfortable, but judging by your face…” He has a nice, calm smile, even though his tone is mischievous and teasing. “It had the opposite effect.”

Iwaizumi tries to wipe the confused expression off his face, but he just ends up frowning. Hayama whimpers out a small ‘Mom’ and Iwaizumi turns away from Oikawa, who’s positively shining, to look at the crowd again.

“Do you remember what she looks like?”

Iwaizumi glances over his shoulder to look at Oikawa. “Same hair colour as you, pink shirt, but… shorter.”

“… So, like me, but shorter,” Oikawa repeats slowly. “Are we looking for my younger sister?”

Iwaizumi’s eyes narrow and Oikawa looks at him innocently. “That was a bad joke.”

“Hey! That was a great joke,” he huffs, and then follows Iwaizumi as he weaves through the crowd. He doesn’t have to look back to know that Hayama is still clinging to Oikawa—he can hear him sniffling now and playing quietly with the doll in his arms. “You just have bad taste.”

“We just met and you’re already insulting me?” Iwaizumi instantly takes back every nice thought he’s had about Oikawa.

“I didn’t say you had bad taste in _everything_. Just jokes.”

“That doesn’t make it any better!” Iwaizumi protests, gritting his teeth. Oikawa giggles behind him and then speeds up his pace so they’re walking side by side, shoulders knocking together. Iwaizumi would move away, but he’d rather be close to Hayama to keep him from feeling unsafe than brushing up against sweaty strangers.

They reach the border of the convention center and the parking lot without finding the kid’s mom and Oikawa hums, looking around. There’s rows and rows of cars ahead of them, but he can’t imagine that Hayama’s mom would still be there, even if that’s where she headed in the first place. It’s been a good twenty minutes since she was lost. He turns and sees the park in the distance, where the crowd is slowly seeping towards as it gets busier and busier.

“Well, she’s definitely not here. Let’s try the park.” Oikawa says, apparently having the same idea.

They make the trek towards the other end of the convention center, towards the park, much slower than they had towards the parking lot. They walk facing the sun now, and Iwaizumi pulls uncomfortably at his mask.

“You should take it off,” Oikawa says and reaches over, lifting the bottom up. Iwaizumi quickly bats his hand away, looking towards the kid to see if he had noticed, but Hayama boy was looking at the ground. At least he stopped crying.

“I can’t,” he answers quietly, tilting his head towards the little boy.

Oikawa makes a little ‘oooh’ sound. “What a shame.”

A few people stop him for pictures on the way there and despite his own protests, Oikawa says ‘yes’ for him every time. Hayama eventually goes back to half-clinging to his leg, apparently being unable to decide whether he wants to stay with Oikawa or Iwaizumi more. He hangs onto both of them, walking in between them and looking at Iwaizumi with glassy, adoring eyes whenever Iwaizumi breaks away to talk to someone else.

He can hear Oikawa giggling in the background every time he has to say his name is ‘Bruce Wayne’ in a horrible accent, too afraid to break character now. He’s in _way_ too deep to go back now.

“Batman,” Hayama asks. Iwaizumi can barely hear his voice over the crowd. He stops Oikawa from walking any further with a small pat to his back, then leans over so he’s close to eye-level with the kid.

“Yeah?”

“What… What if we never find my mom?”

Oikawa makes a cooing noise and Iwaizumi quiets him with a sharp kick to the ankle.

“She’s here somewhere.” Iwaizumi reaches up and then hesitantly pats Hayama’s head the same way Oikawa did. His shoulders go slack and he nods pitifully, swinging the arms of his Batman doll back and forth. “And if we can’t find her, I’ll… scale onto the roof and call out to her.”

He kicks Oikawa in the calf again so he won’t laugh.

“Really?” Hayama sniffles.

“Really.”

“My legs are getting tired,” he mumbles. “Can you carry me?”

Iwaizumi is about to kick Oikawa again, but he’s not laughing. He’s covering his mouth with his hand, undeniably smiling underneath his palm by the way his eyes crinkle.

“Alright. Just until we find your mom,” Iwaizumi concedes. Hayama passes his Batman doll to Oikawa, who takes it with a look of mild confusion and amusement.

Iwaizumi scoops Hayama up in his arms, allowing the boy to settle into a comfortable position. He rests his head against Iwaizumi’s chest and then reaches out for his doll again. He tucks it against him and then shuts his eyes and Iwaizumi takes this as a signal to keep walking.

“You’re like a real father, huh?” Oikawa tilts his head, smiling with a kind of fondness that makes the little hairs on the nape of his neck stand up.

“Not really,” he mutters, running his fingers through Hayama’s hair absently. The boy is half-asleep in his arms already, probably tired from walking and the intense heat.

“Don’t worry, _Iwa-chan_.” Oikawa winks at him. “I won’t tell everyone that the Batman cosplayer with the scary, deep voice is actually a huge softie.”

Iwaizumi frowns, but it’s not noticeable from underneath his mask. “Being nice to a child is being soft?”

Oikawa mumble something like ‘so mean’ under his breath as they reach the border of the park. There’s a hoard of people in the area now, and over a dozen with red hair. But none of them have the right shade—Iwaizumi knows exactly what it looks like. He only has to look over at Oikawa to see it, although the other boy is clearly taller than Hayama’s mom, with pinker lips and a more handsome face.

“Is that a wig?” he asks curiously. Oikawa guides Iwaizumi inside the park, teetering on his tippy-toes to tower over everyone else in the crowd.

“Of course.” He looks back at Iwaizumi and laughs. “I’m not dressing up today, but I still need to fit in.”

Iwaizumi found it more funny how ‘fitting in’ here meant dressing up than the fact that Oikawa thought he needed to wear a wig to fit in. He couldn’t imagine any hairstyle that Oikawa would look bad in—except a mullet, maybe.

“Why? Do you dress up as Batman every day, Iwa-chan?”

Iwaizumi shifts Hayama in his arms, careful not to wake him from his sleep. “Don’t call me that.” Oikawa sticks out his tongue in return, his pretty face contorting into a funny-looking retort. “And no, of course not. I’m in university too.”

“Oh? What for?”

“Sports psychology.”

Oikawa couldn’t look more shocked in that moment. It’s almost offensive how surprised he is. “Do you play? Ah, well…” He pinches Iwaizumi’s arm lightly. “I suppose I don’t need to ask that.”

Iwaizumi’s arms tense and he holds onto Hayama tighter. He didn’t mind people talking about his body—he worked out a lot, and it was nice to be recognized. But Oikawa’s touch was different. Gentle, but teasing, a perfect match to his voice and appearance. It made his stomach curl oddly and his heart pound at a strange pace.

They make their way through the park, wading through crowds of animated friends and cosplayers posing for pictures. He breathes a sigh of relief when they finally get to the shade under the trees, but he can’t feel happy just yet when he’s still carrying Hayama with him.

“I don’t see her,” Oikawa clicks his tongue, eyebrows furrowed. “Dark red hair, pink shirt, right? Not dressed up?”

“Just dressed normally,” Iwaizumi confirms.

Oikawa runs his fingers through his hair, looking at Hayama with a distressed expression. “You really shouldn’t have promised him you’d scale the building if we didn’t find his mom.”

“Then let’s find his mom before it comes to that.”

They circle the long way around the park and end up back where they started; at the bench in front of the entrance to the convention center. Iwaizumi lays Hayama on the bench, slipping off his cape to use as a blanket for him.

“You’re a volunteer, don’t you have a megaphone?”

“Iwa-chan,” he starts. Iwaizumi glares with as much energy as he can muster after doing a lap around the area in full leather. “If I had a megaphone, I’d have used it before we walked around.”

“Well, I can’t walk around again in this. It’s way too hot.”

“This is where you lost her, right?” Oikawa sits down on the bench, stroking Hayama’s hair. “She’ll have to come back sometime.”

As if on cue, Iwaizumi almost jumps when he hears a loud cry of “Hayama-kun!” in a thankfully familiar voice.

Hayama’s open slowly, blearily, as he adjusts to the bright shine of the sun. He sits up, throws the cape off of him, and then rubs his eyes and Oikawa looks at Iwaizumi, grinning from ear to ear when Hayama sobs ‘Mom!’ and jumps off the bench and into her arms.

“Hayama-kun…” She holds him against her chest, then picks him up and presses a dozen kisses to his forehead. “Where did you run off to?”

“I-I couldn’t find you,” Hayama rubs his fists against his eyes, lower lip wobbling. “And we went to look for you, a-and it was hot outside, and my legs got tired, so Batman carried me.”

Hayama’s mom shushes him, petting his hair in the same way Oikawa did. “Um, Batman,” she’s still smiling, and Iwaizumi finds himself smiling back in relief. “Thank you. I have no idea what happened… I saw an old friend and talked to her for a few minutes, and when I came back, you guys were gone!”

 _That must have been a long few minutes_ , Iwaizumi thinks, but he nods quickly. “It wasn’t bothersome. He’s… a really nice child.”

Hayama’s mom blushes prettily and then turns to the little boy. “Your dad is going to be waiting for us. Are you ready to go home now?”

Hayama waves his Batman doll in the air, jumping on his toes. “Yes!”

“Thank you,” his mom says, and Iwaizumi can hear how grateful she is. He thinks, briefly, about what it would be like to lose his cat, who is, essentially, his child. He decides not to think too much about it when he starts to feel sick just at the thought. “If anyone was going to get lost with him, he’s probably happy it was Batman. What do you say, Hayama-kun?”

Hayama turns to him, fidgeting with the Batman doll before gazing at him with a look of sincere appreciation. Iwaizumi’s heart swells and he brushes his fingers over Hayama’s hair one last time. “Thank you, Batman.”

“Anytime.”

Hayama and his mom bow and then say their goodbyes after he gives her the marker and one last smile, the little boy running around his mom in joy and tugging on her sleeve. He watches them until they become small figures in the distance, disappearing into the crowd.

He turns back to Oikawa, who, as far as Iwaizumi knows, hasn’t moved since Hayama’s mom retrieved him.

“That’s disappointing. She isn’t single… but you guys talked so sweetly.”

Iwaizumi’s face turns a bright red. “What? I’m not—I wasn’t making a pass at her or anything…!”

Oikawa lowers his voice in a bad imitation of Iwaizumi’s, “He’s a really nice child.”

“I wasn’t… I’m probably not going to get through to you even if I try.” He’d frown and slide back onto the bench, over his cape, setting his bag on the floor. “Thanks for the help.”

Oikawa leans in closer, pouting. “Where’s my reward?”

“What reward? You didn’t even do anything, in the end!”

“But you just thanked me for my help!”

Iwaizumi groans and covers his forehead with his palm. “It’s called being nice.”

Oikawa leans in even closer—now way too close in Iwaizumi’s personal space. He shifts away, mustering a frown. “What?” Iwaizumi asks.

“Can I see you with your mask off?” Oikawa reaches out and fingers the bottom of Iwaizumi’s mask. He finds himself just sitting there, a bit uncomfortably because of how hard his heart races in his chest.

“You don’t want money?”

Oikawa scoffs. “What kind of a person do you take me for? I’m a volunteer, not a scam artist.” His eyes, a deep and dark brown, land on Iwaizumi’s face. “I’ll take off my wig, if you really want.”

Iwaizumi pauses for one tense moment, Oikawa’s fingers gliding over his lips.

 _… Holy shit,_ he realizes, _he’s flirting with me._

And Iwaizumi was flirting _back._

He swallows what feels like a weight lodged in his throat and nods, “Deal.”

It feels absolutely blissful to be able to take the mask off after hours of wearing it outside. Oikawa peels the dreaded thing off his face and Iwaizumi helps him slip the whole thing off entirely.

“Mm…” Oikawa smiles calmly, tracing Iwaizumi’s jawline with his fingers, a feather-light touch that makes an unfamiliar kind of heat rise to his cheeks. “Unfortunately handsome,” he decides on saying.

“U-Unfortunately?!”

Oikawa cocks his head and bats his eyelashes. “It means you’ll look even better when you don’t look like a sweaty tomato.”

Iwaizumi’s eyes narrow as Oikawa leans back, laughing. He reaches up to his hairline and then tugs off the wig and the hair net, pulling away the pretty red hair to reveal fluffy and wild light-brown tresses. Oikawa shakes his head and runs his fingers his hair a few times. He looks different, but not in a bad way—decidedly more masculine with his hair shorter, but still breathtaking.

Iwaizumi tugs awkwardly at his collar when Oikawa looks back at him. “So,” he smirks. “What do you think?”

“Are you fishing for compliments?”

Oikawa stuffs the wig and hairnet into his bag and then rests his back against the wall. “Is it that bad?” he pouts.

Iwaizumi rubs one of his burning cheeks. “I didn’t say that.”

“So, you think I’m attractive?”

“… I didn’t say that either!”

Oikawa throws his head back and laughs, closing his eyes as if he was basking in the warmth of the sun. The rays of light fall onto his face and he would look angelic if Iwaizumi didn’t know any better now.

“Let’s get some coffee sometime.” Oikawa looks at him, gaze smoldering far more than the sun in that moment. “My treat.”

Iwaizumi’s fingers dig into his thigh—he hasn’t gone out with anyone in a long, long time, too busy with school to go out just for that purpose, and he’s never been actively interested in finding a partner. But Oikawa was funny, an overwhelming mixture of snarky and cute, and Iwaizumi thinks about what his day would have been like if Oikawa hadn’t joined him. Probably a lot worse.

“… Okay,” he agrees, slowly, as if treading on foreign territory. “Your treat.”

They exchange numbers and Oikawa puts himself down as ‘Oikawa~ ☆” in Iwaizumi’s phone, before excusing himself to go back to his actual volunteering work. He blows Iwaizumi a kiss as he walks away, and even if Oikawa’s mouth is nowhere near his, his lips still tingle as if he was just kissed.

Later, when he’s back at home packaging up his costume for another few months in the closet, he gets a text from Oikawa.

‘you didn’t tell me you used to be a volleyball player!!!!!!! also we live in the same area’

Iwaizumi pauses his work and sits down on his bed, pulling out his phone from the charger to reply.

‘You looked me up?’

‘you didn’t tell me anything about yourself and you seemed shy so i didn’t want my first text to you to be where do you live? :P’

He doesn’t have a chance to reply before the next text comes.

‘you know the coffee shop in downtown with the cat statue in front and the ppl working there always draw bad cats on the sign in front? are you free tomorrow between three and five let’s meet there’

‘Yeah, and… yeah. That sounds good to me.’

‘omg you type so cutely :333c okay!! see you tomorrow iwa-chan~ call me if you get lost… or lonely’

‘That better not have been innuendo.’

‘… See you tomorrow, Oikawa.’

When he finishes organizing his costume inside his closet, he realizes things like this—making kid’s dreams come true and meeting loud, wispy-haired boys—were why he put himself through the exhaustion of getting up at five o’clock in the morning to dress up and drive two cities away.

And when he meets Oikawa for coffee the next day and they end up having their first kiss in a gym, forty minutes from the coffee shop they started in, Iwaizumi decides it was definitely worth it.

**Author's Note:**

> kudos/comments/etc are all appreciated! <3


End file.
